LCD module and a combination switch using the same

ABSTRACT

An LCD module is associated with a pair of switches, one of which is depressed by pressing the LCD module to swivel in a seesaw operation. The LCD module has a front panel having a larger thickness than and thus capable of protecting the LC layer and the rear panel against a reasonable external load for pressing the front panel for switching. The LCD module is suited for use in a portable terminal having a smaller space for switches and LCD module.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] The present invention relates to a liquid crystal display (LCD)module and, more particularly, to the structure of a combination switchincluding the LCD module.

[0003] (b) Description of the Related Art

[0004] In recent years, portable terminals, such as a portable dataassistant or a mobile telephone, have been developed for achievingsmaller dimensions and higher performances as well as excellentappearance using decorations. The higher performances should includehigher functions of the portable terminals as well as simplification ofthe operation thereof. The simplification of the operations is partiallyachieved by large dimensions of a display module, such as an LCD module,which displays a guidance image for the operations.

[0005] In the circumstances as described above, the LCD module used inthe portable terminal has increasingly larger dimensions. Among otherparts of the portable terminal, the LCD module has a lower mechanicalresistance against an external force, and thus is generally protected byan overcoat layer. The provision of the overcoat layer increases thethickness of the portable terminal, however. In addition, increase ofthe number of operations in the portable terminal may necessitateallocation of a single switch button to a plurality of functions, whichcomplicates the operation itself of the portable terminal and confusesthe user.

[0006] The display on the LCD module of the portable terminal isgenerally switched for providing a variety of operational information inview of the increase of the number of functions and services provided bythe portable terminal. Examples of such a switching of the display forthe operational information include a switching between a waiting modeat which the LCD module displays time information, residual batterypower, antenna sensitivity or mode information such as a manner mode orvibration mode of the portable terminal, and a calling mode at which theLCD module displays a telephone number. The switching of the display onthe LCD module is implemented by a changeover switch which switchesbetween a plurality of installed programs.

[0007] The increase in the functions of the portable terminalnecessitates an increase in the display area of the LCD module in theportable terminal. The provision of the changeover switch as well asprovision of a number of other operational switches on a housing orcasing of the portable terminal decreases the area of the housing to beallocated to the LCD module. Thus, a trade-off arises between a largerdisplay area for the LCD module and the provision of a number ofoperational switches.

[0008] JP Patent No. 3019893 is directed to a camera having an installedzoom lens and implies a solution for the trade-off in the portableterminal as described above. The described camera includes a substrate,an LCD module formed thereon, and a changeover switch or seesaw switchmounted on the substrate for switching the zooming direction of the zoomlens. The substrate further mounts thereon a large number of electricinterconnections.

[0009] The seesaw switch includes a pair of electric contactssandwiching therebetween the LCD module and normally urged to a neutralposition, and an arched lever made of a transparent material forallowing the LCD module to be observed therethrough and having a pair ofprotrusions which respectively abut against the electric contacts at theoperating positions of the seesaw switch. The swivel axis of the leverof the seesaw switch extends parallel to the camera body or casing andoverlies the center of the LCD module.

[0010] The seesaw switch effects abutment between each of the electriccontacts and a corresponding one of the protrusions by a swiveloperation, while allowing the zooming direction of the zoom lens to beobserved on the LCD module. The LCD module is formed on a substrate,which is fixed onto the camera body, for indicating a variety ofoperational information including the zooming direction.

[0011] The described camera includes the lever of the seesaw switch,which also functions as a protective member for protecting the LCDmodule against an external force. This allows reduction of the totalarea for the operational switch and the LCD module, thereby solving thetrade-off between the operational switches and the LCD module in thecamera.

[0012] If the technique as described above is used in a portableterminal for solving the trade-off as described before, there arises aproblem in that the structure of fixing the substrate mounting thereonthe LCD module and the seesaw switch onto the camera body iscomplicated. In addition, the structure of the lever of the seesawswitch overlying the LCD module restricts the direction of the movementof the lever, which cannot be moved or slid in the direction parallel tothe substrate because the sliding movement of the lever shields the endportions of the LCD module.

SUMMARY OF THE INVENTION

[0013] In view of the above problem in the conventional LCD module, itis an object of the present invention to provide a combination switchincluding an LCD module and an associated switch member capable of beingoperated by the movement of the LCD module without affecting thefunction of the LCD module.

[0014] It is another object of the present invention to provide an LCDmodule for use in such a combination switch.

[0015] The present invention provides a liquid crystal display (LCD)module including a transparent front panel, a rear panel and a liquidcrystal (LC) layer sandwiched between the transparent front panel andthe rear panel, the transparent front panel having a central areaopposing areas of the LC layer and the rear panel and a peripheral areaextending from the central area, the transparent front panel acting asan overcoat for protecting the LC layer and the rear panel against areasonable external force.

[0016] The present invention also provides a combination switchstructure including: a liquid crystal (LCD) module including atransparent front panel, a rear panel and a liquid crystal (LC) layersandwiched between the transparent front panel and the rear panel, thetransparent front panel having a central area opposing areas of the LClayer and the rear panel and a peripheral area extending from thecentral area; and a switch member operated by a movement of theperipheral area when the transparent front panel is applied with anexternal force.

[0017] In accordance with the combination switch of the presentinvention, the trade-off between the number of switches and a largerarea of the LC module can be solved due to the functions and thestructure of the combination switch.

[0018] The above and other objects, features and advantages of thepresent invention will be more apparent from the following description,referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIGS. 1A to 1C are a front view, a bottom view, and a side view,respectively, of an LCD module according to a first embodiment of thepresent invention.

[0020]FIGS. 2A to 2C are a front view of an example of the LCD module ofthe first embodiment attached onto a casing, a sectional view takenalong line B-B in Fig. FIG. 2A, and a sectional view taken along lineC-C in FIG. 2A, respectively.

[0021]FIGS. 3A to 3C are a front view, a bottom view, and a side view,respectively, of another example of the LCD module of the firstembodiment attached onto a casing.

[0022]FIGS. 4A to 4C are a front view, a bottom view and a side view,respectively, of an LCD module according to a second embodiment of thepresent invention.

[0023]FIGS. 5A to 5C are front view, a bottom view and a side view of acombination switch including a seesaw switch in combination with the LCDmodule of the second embodiment.

[0024]FIGS. 6A and 6B are front view and a bottom view, respectively, ofthe combination switch of FIGS. 5A to 5C, showing operation thereof.

[0025]FIG. 7 is a bottom view of the combination switch of FIGS. 5A to5C, showing an operational step.

[0026]FIGS. 8A to 8C are a front view, a bottom view and a side view,respectively, of an LCD module according to a third embodiment of thepresent invention.

[0027]FIGS. 9A and 9B are a front view and a bottom view, respectively,of a combination switch including one of the LCD modules of theembodiments of the present invention.

[0028]FIGS. 10A and 10B are a front view and a bottom view,respectively, of a combination switch including one of the LCD modulesof the embodiments of the present invention.

PREFERRED EMBODIMENTS OF THE INVENTION

[0029] Now, the present invention is more specifically described withreference to accompanying drawings, wherein similar constituent elementsare mostly designated by similar reference numerals.

[0030] Referring to FIGS. 1A to 1C, an LCD module, generally designatedby reference numeral 10, according to a first embodiment of the presentinvention includes a transparent front panel 11, a transparent rearpanel 12, and an LC layer 13 sandwiched therebetween to form a unitarybody of the LCD module 10. The rear panel 12 has a relatively smallthickness, and may be made of a non-transparent material.

[0031] The front panel 11 has a function for protecting the LC layer 13against a reasonable external load 15 generally applied to the portableterminal 10, such as a portable data assistant or a mobile telephone. Asis well known, if the front panel 11 is deformed by the external load15, the LC layer 13 is also deformed to affect the image passed by theLC layer 13. For prevention of such a deformation, the front panel 11has a thickness sufficient for preventing the external load 15 fromexerting an adverse influence to the LC layer 13. The front panel 11 hasan area larger than the areas of the rear panel 12 and the LC layer 13,which are substantially same. The peripheral area 16 of the front panel11 protruding from the edges of the rear panel 12 and the LC layer 13 isreferred to as a flange 16 in this text, the flange 16 including fourflange portions corresponding to the four edges of the LCD modules 10.

[0032] The term “external load” or “reasonable external load” as usedherein means a load inadvertently applied to the portable terminal 10,such as a load applied when the user sits on a seat with the portableterminal 10 received in a rear pocket of trousers, a load applied by aluggage, for example, to the portable terminal 10 received in a leatherbag, or a force applied by the gravity when the portable terminal 10falls to the ground. Thus, the external load has an unspecified point ofapplication on the transparent front panel. FIG. 1 shows such a point ofapplication of the external force 15 by reference numeral 17.

[0033] Referring to FIGS. 2A to 2C, when the LCD module 10 of the firstembodiment is to be fixed onto a casing 18 having an opening 14, a pairof through-holes 19 a and 19 b formed in the front panel 11 at theflange portions thereof are used in combination with respective screwsor bolts 20 a and 20 b. In this case, if a reasonable external load 15is applied to the front panel 11 at an arbitrary point 17, the externalload 15 hardly damages the LC layer 13 and the rear panel 12 due tosubstantially no deformation of the front panel 11 having a sufficientthickness.

[0034] Referring to FIGS. 3A to 3C, the LCD module 10 of the firstembodiment is attached onto a casing 18 having an opening 14 forallowing a swivel movement or seesaw movement of the LCD module 10around a swivel axis X-X extending in the direction parallel to thefront surface of the casing 18 or the front panel 11. The swivel axisX-X is implemented by a pair of protrusions 21 a and 21 b formed on thetop and bottom of the front panel 11 at the flange portions 16 a and 16b thereof. The pair of protrusions 21 a and 21 b are supported on a pairof bearings 22 a and 22 b fixed onto the casing 18 so that the LCDmodule 10 is allowed to move in a seesaw fashion around the swivel axisX-X with respect to the casing 18.

[0035] In the configuration of the combination switch of FIGS. 3A to 3Cincluding the LCD module 10, an external load 15 applied onto the frontpanel 11 at a point 17 a located in the vicinity of or on the axis X-Xdoes not swivel the LCD module 10. In addition, the external load 15does not substantially generate a deformation or damage on the rearpanel 12 and the LC layer 13 due to the sufficient thickness of thefront panel 11.

[0036] If an external load 15 is applied on the front panel 11 at apoint 17 b or 17 c apart from the swivel axis X-X, the LCD module 10 isswiveled without involving a damage on the LCD module 10.

[0037] Referring to FIGS. 4A to 4C, an LCD module 10A according to asecond embodiment of the present invention is similar to the LCD module10 of the first embodiment except for a step 31 formed in the vicinityof the periphery of the front panel 10. The step 10 is such that thefront portion 11 a of the front panel 10 is smaller in size than therear portion 11 b of the front panel 10. In other words, the step 31 isformed by different thicknesses of the front panel 11, wherein the innerarea of each flange portion 16 a-16 d of the front panel 11 has a largerthickness than the outer area of the each flange portion 16 a-16 d.

[0038] Referring to FIGS. 5A to 5C, the LCD module 10A of the secondembodiment is attached onto a casing 18 having an opening 14 so that theLCD module 10A is allowed to swivel around the swivel axis X-X, with thefront surface of the front panel 11 received in the opening 14. Theswivel axis X-X is implemented by a pair of fulcrums 24 a and 24 bresiding on the top and bottom flange portions 16 a and 16 b of thefront panel 11 of the LCD module 10A. The front panel 11 is supported atboth the side edges thereof by the casing 18 by means of a pair ofsprings 28 a and 28 b disposed between the casing 18 and the frontsurface of the flange portions 16 a and 16 b. The rear surface of thefront panel 11 is supported against the springs 28 a and 28 b at thefulcrums 24 a and 24 b, located on the swivel axis X-X, by a pair ofsupport members 32 a and 32 b formed on a substrate 26. The frontsurface of the central area of the front panel 11 is flush with thefront surface of the casing 18 at the normal position of the LCD module10A. The periphery of the front panel 11 having a lower thickness thanthe central area is received inside the casing 18.

[0039] A pair of changeover switches 25 a and 25 b are disposed on thesubstrate 26 at the locations where the right and left edges of the rearsurface of the front panel 11 abut the changeover switches 25 a and 25 bafter the swivel of the LCD module 10 for on/off operations of theswitches 25 a and 25 b. The changeover switches 25 a and 25 b are usedfor switching between programs which display different information onthe LCD module 10A.

[0040] It is to be noted that a pair of support members may be formed onthe casing 18 for supporting the flange portions 16 a and 16 b of thefront panel 11 instead of the support members 32 a and 32 b on thesubstrate 26. In such case, the fulcrums reside on the rear surface ofthe casing 18.

[0041] Referring to FIGS. 6A to 6C, there are shown swiveling directionsof the LCD module 10A of the present embodiment by arrows 23 a and 23 b.

[0042] If an external force 15 is applied to the LCD module onto a point17 a of the front panel 11 near the swivel axis X-X, the LCD module 10Astays at the normal position due to a small moment around the swivelaxis X-X. The applied force is transferred onto the casing 18 and/orsubstrate 26. The sufficient thickness of the front panel 11 allows therear panel 12 and the LC layer 13 to be substantially free fromdeformation. If a pair of external forces 15 are applied at both points17 b and 17 c so that both the external forces 15 cancel the moment ofeach other with respect to the swivel axis X-X, the LCD module 10A staysat the normal position as well.

[0043] For operating one of the changeover switches 25 a and 25 b, anexternal force 15 is applied onto the front panel at point 17 b or 17 c,which is well apart from the swivel axis X-X. The LCD module 10A isswiveled by the external force 15 in a seesaw function to allow one ofthe rear edges thereof to abut one of the changeover switches 25 and 25b, after breaking the mechanical balance between the springs 25 a and 25b, as shown in FIG. 7. Each switch 25 a or 25 b has an inherent functionfor switching the image on the LCD module 10.

[0044] The front panel 11 may be made of any of glass or plastic resinmaterials for achieving a variety of shapes for the flange portion. Thenumber of flange portions may be two or four in the front panel, so longas the flange portions oppose each other.

[0045] In an alternative, a combination of top or bottom flange and aright or left flange may be formed in the front panel 11 if the flangeportions are not used for swiveling the LCD module 10 and simply usedfor fixing.

[0046] The rear panel 12 may be either transparent or non-transparent.The front panel 11 may have any shape such as a polygon. The LC layer 13may be made of any LC materials or an organic electroluminescencematerial.

[0047] Referring to FIGS. 8A to 8C, an LCD module 10B according to athird embodiment of the present invention includes a front panel 11having a first portion 11 c and a second portion 11 d, a rear panel 12,and an LC layer 13 sandwiched therebetween, wherein the first portion 11c has a larger thickness and functions as a protective overcoat forprotecting the second portion 11 d, the rear panel 12 and the LC layer13 against an external load. The protective overcoat 11 c also has alarger area than the area of the second portion 11 d, the LC layer 13and the rear panel 12, as viewed in the direction normal to the panels.The protective overcoat 11 c has flange portions 16 a-16 d protrudingfrom the edge of the second portion 11 d in the direction parallel tothe panels.

[0048] In the LCD module 10B of the present embodiment, the secondportion 11 d of the front panel 11 and the rear panel 12 havesubstantially the same thickness and the same dimensions. This structureallows the fabrication process to be simplified.

[0049] The combination switch structure having the LCD module of thepresent invention may be of a single-switch type or a slide-switch typeother than the seesaw-switch type shown in FIGS. 5A to 5C.

[0050]FIGS. 9A and 9B show a single-switch type combination switchstructure having the LCD module 10 of FIGS. 1A to 1C. A pair of elasticmembers or springs 42 a and 42 b are provided between the flangeportions 16 c and 16 d of the front panel 11 and the substrate 26mounting thereon the LCD module 10, urging the LCD module 10 toward thefront side. A changeover switch 41 is disposed at the center of the rearsurface of the rear panel 12 so that the changeover switch 41 is in thenormal state thereof by the function of the springs 42 a and 42 b. Thecasing 18 having an opening 14 for exposing the front panel 11 of theLCD module 10 is fastened to the substrate 26 by screws 43 a and 43 b.

[0051] In operation, when the LCD module 10 is pressed toward the rearside against the springs 42 a and 42 b, the changeover switch 41 is madeon.

[0052]FIGS. 10A and 10B show a slide-switch structure having the LCDmodule 10A of the second embodiment.

[0053] The flange portions 16 a and 16 b of the LCD module 10A aremounted on a pair of guide rails 51 a and 51 b, which are fixed onto asubstrate 26, so that guide rails 51 a and 51 b allows the LCD module10A to slide between two positions at which the steps 31 of the flangeportions 16 c and 16 d act as stoppers on the edges of the opening 14.The LCD module 10A has a lever 53 which forces the switch 52 to makeopen or close during the slide movement of the LCD module 10A betweenthe stoppers.

[0054] The sufficient thickness of the front panel 11 protects the LClayer 13 and the rear panel 12 against the external force for shiftingthe LC module 10A between the stoppers.

[0055] Since the above embodiments are described only for examples, thepresent invention is not limited to the above embodiments and variousmodifications or alterations can be easily made therefrom by thoseskilled in the art without departing from the scope of the presentinvention.

What is claimed is:
 1. A liquid crystal display (LCD) module comprisinga transparent front panel, a rear panel and a liquid crystal (LC) layersandwiched between said transparent front panel and said rear panel,said transparent front panel having a central area opposing areas ofsaid LC layer and said rear panel and a peripheral area extending fromsaid central area, said transparent front panel acting as an overcoatfor protecting said LC layer and said rear panel against a reasonableexternal force.
 2. The LCD module as defined in claim 1, wherein saidperipheral area has a plurality of holes for receiving screws.
 3. TheLCD module as defined in claim 1, wherein said peripheral area includesa pair of flange portions extending from said central area.
 4. The LCDmodule as defined in claim 1, wherein said central area has a thicknesslarger than a thickness of said peripheral area, whereby a step isformed in a vicinity of a boundary between said central area and saidperipheral area.
 5. The LCD module as defined in claim 1, wherein saidtransparent front panel comprises a first portion having a thicknesssubstantially equal to a thickness of said rear panel, and an secondportion covering said first portion.
 6. A combination switch structurecomprising: a liquid crystal (LCD) module including a transparent frontpanel, a rear panel and a liquid crystal (LC) layer sandwiched betweensaid transparent front panel and said rear panel, said transparent frontpanel having a central area opposing areas of said LC layer and saidrear panel and a peripheral area extending from said central area; and aswitch member operated by a movement of said peripheral area when saidtransparent front panel is applied with an external force.
 7. Thecombination switch structure as defined in claim 6, further comprisingat least one elastic member for urging said LCD module, wherein saidswitch member is pressed by pressing said transparent front panelagainst said elastic member.
 8. The combination switch structure asdefined in claim 7, wherein said at least one elastic member includes apair of springs, and said LCD module swivels around a swivel axis whensaid transparent panel is pressed.
 9. The combination switch structureas defined in claim 6, further comprising a guide member fixed withrespect to a casing for guiding said LCD module along a surface of saidcasing, wherein said switch member is operated by a slide movement ofsaid peripheral area.